The present invention relates to a fuel injection pump which may be, but is not limited to, the distribution type.
In a distribution type fuel injection pump such as disclosed in U.S. Pat. No. 3,906,916, a fuel control sleeve is positioned by flyweights to control the amount of fuel injection in accordance with engine speed. Flyweights urge a governor rod toward a tension lever as the engine speed increases. At a certain engine speed, the governor rod engages the tension lever and moves the same against the force of a governor spring to move the sleeve in a direction to decrease the amount of fuel injection.
A start lever is rotatably mounted on a same pin as the tension lever and is urged by a start spring to abut against the end of the governor rod. Thus, the flyweights must first oppose the force of the start spring. At a certain engine speed, the start lever is moved by the governor rod to abut against the tension lever, after which point the flyweights must oppose the combined forces of the start spring and governor spring.
A problem has existed in this type of pump in that the start lever tends rotate or twist about an axis perpendicular to the pin instead of being moved straight by the governor rod. This has a substantial adverse effect on the accuracy of fuel injection control. After a long period of use, the governor rod forms a concave depression in the start lever which yet further contributes to inaccurate fuel injection control.